I have been on MN for nearly a decade (sporadically) but have recently namechanged.
Without banging on for pages about the headfuckery that I have been subjected to, here is a nutshell of recent events that have led me to consider NC or LC with my mother:
I am the eldest of 5 (+1 half sister who is thankfully not part of the situation) and fit nicely into the Scapegoat stereotype, the second youngest is the Golden Child and the remaining siblings are what I recently discovered is called Flying Monkeys - honestly, for such a horrendous situation they do come up with some god-awful names for it all!!
My mother has, amongst many other vile abusive tactics, couched vile lies about me in a thin veil of concern, for as long as I can remember - lots of "I'm so concerned about GHW, she is such a horrible person/social climber/compulsive liar/bad parent etc etc" to anyone who will listen, including my closest friends. Ironic really as she seems to be describing herself to a T!!
I moved to the other end of the country a few years ago and hoped that the distance would help, but on a recent visit to see her and friends in the local area, I discovered she had upped her slagging-off tactics considerably in my absence. I felt that confrontation was my only option but having researched the dynamic, realised that expressing any upset would be the worst thing to do. Instead I went for the fighting fire with fire option and turned it around on her - basically saying that I didn't care what she said about me, but that countless people had told me what she was saying and I was becoming increasingly concerned that they were regarding her badly for being so unkind about her own child. Rather sneaky of me to play on one of the biggest fears of someone with NPD, but I knew it would be the only way to make her consider altering her behaviour. I kept my voice calm and emotionless but hadn't anticipated such a violent reaction from her. She screamed and shouted abuse, then flew at me as if to hit me before suddenly checking herself. I almost wish that she had hit me as she wouldn't have been able to lie her way out of that! She then drove off and didn't return until after DH, the DC and I had left - although she did call the goldenchild who made a very ostentatious show of rushing upstairs and whispering urgently 
I haven't spoken to my mother since this incident and would happily never speak to her again, if it weren't for the fact that NC with her would mean losing contact with my siblings over whom she has a great deal of control. I am also mindful of the impact that NC would have on our DC, who adore their uncles and aunts and are currently unaware of the dynamics. She has called our home a couple of times to speak to DS (for his birthday) and once to talk to me (DH told her I was out!), but I really don't have the energy to talk to her. Does anyone have experience of tackling NPD parents in a healthy way?